Amidoalkanesulfonic acid derivatives are useful as lime soap dispersants. Among others, unsaturated amidoalkanesulfonic acid derivatives are known to have wide applications as raw materials for the manufacture of water-soluble polymers (for example, flocculents, dispersants, adhesives and thickeners) and as raw materials for the manufacture of ion exchangers such as ion exchange resins.
Conventionally, there are two well-known methods for preparing amidoalkanesulfonic acid derivatives. One of them involves the reaction of an aminoalkanesulfonic acid or its derivative with acrylic acid chloride and the other involves the reaction of a nitrile, an olefin and concentrated sulfuric acid including fuming sulfuric acid.
However, the former method requires expensive raw materials and, therefore, is not suitable for industrial practice. On the other hand, the latter method is currently used in the industrial production of 2-acrylamido-2-methylpropanesulfonic acid (hereinafter abbreviated as AMPS). However, although this method is suitable for the preparation of AMPS, it is not yet perfected as a technique fully applicable to the preparation of other amidoalkanesulfonic acid derivatives. One reason for this is that the olefin used in the latter method generally has a very high degree of cationic polymerizability. Thus, the method is practicable in the case of isobutene, but other olefins used as raw materials tend to undergo side reactions (cationic polymerization and the like) in concentrated sulfuric acid and fail to produce satisfactory results.